1. Field of the Invention
Embodiments of the present invention relate to a method, medium, and apparatus for a self-propelled mobile unit with obstacle avoidance during wall-following algorithm.
2. Description of the Related Art
Many home appliances operate at a fixed position. However, if the home appliances were not fixed, their operations could be performed more efficiently. For example, in the case of a humidifier, an air cleaner, or a vacuum cleaner it maybe desirable or beneficial for these devices to perform their operations while moving. Thus, many self-propelled mobile unit mechanisms have been proposed.
For example, U.S. Pat. No. 649,754 discusses a motion mechanism for allowing a self-propelled mobile unit to recognize a position and move thereto, through the use of an installed recognition mark on a ceiling. Here, a position in space can be recognized, but it is difficult to avoid obstacles. Also, when the self-propelled mobile unit moves under a table it cannot detect the overhead mark and thus may have navigation problems.
Meanwhile, U.S. Pat. No. 5,920,172 discusses a path finding method for a self-propelled mobile unit. Here, when the self-propelled mobile unit encounters an object, it turns a predetermined angle and then returns to a point of departure. If the object is a table and a gap between legs is wide, the self-propelled mobile unit may move under the table. Only when the object has a polyhedral structure, such as a box or a sphere, can the self-propelled mobile unit detect and avoid the object.
However, the gap between legs of the chair, table, or desk, in offices or homes, may typically be wide, such that they may not be recognized as obstacles. Accordingly, there is a need for a method of avoiding such obstacles during a wall-following operations.